Vaillant was born on April 5, 1891, in Saignelégier. He was light bay, stood 162 cm tall, and possessed an excellent topline. He was powerful and had a very gentle temperament.
According to the 1894 report of the Cantonal Commission, he possessed all the qualities of a good breeding stallion. He had already been noticed at the two-year-old competition the previous year, where he received the maximum score. Until 1898, he continued to obtain the maximum score at shows. Vaillant was the product of inbreeding: the mare Poulette was the mother of both of Vaillant's parents. This certainly explains the frequent cramps described by his owner.
He was sold at the age of 9 to the canton of Fribourg for the substantial sum of 5,000 Swiss francs (CHF) (the construction of a farmhouse in the Jura region cost 15,000 CHF at the time).